Mississippi had the highest rate of obesity, with 29.5 percent of adults classified as obese in 2004. In Colorado, the slimmest state, just 16 percent of adults are obese, the Trust for America's Health found.

Oregon's rate of 21 percent was unchanged.

"We have a crisis of poor nutrition and physical inactivity in the U.S. and it's time we dealt with it," said Shelley Hearne, executive director of the group.

An estimated 119 million Americans, or 64.5 percent, of adults are either overweight or obese and the rate has been rising steadily every year. The percentage of obese adults rose from 23.7 percent in 2003 to 24.5 percent in 2004, reports Reuters.

According to Forbes, an outside expert put it even more starkly.

"Obesity is arguably the gravest public health threat in the United States today," said Dr. David L. Katz, the director of the Prevention Research Center at Yale University School of Medicine.

Obesity is among the root causes of almost every major chronic disease you face, including diabetes, cardiovascular disease, breathing disorders and cancer, he added.

"This new report indicating that we are not doing enough to control obesity should come as no surprise," Katz said. "We are, in fact, doing quite a lot to make obesity worse. New technologies that decreases our physical activity; new processed food products that combine tasty calories with poor nutrition; time wasted on silly distractions such as fad diets, and policies and politics that squeeze physical activity and opportunities for good nutrition out of the typical work and school day all conspire against us."